Its the gift that keeps on giving the return of investment on a person you train or goes to school on their own is limitless they could expand your company or gain more market share for you. Machinery and equipment on the other hand can only give what has been put into them and begins to depreciate the moment you start use them.
Yes, human capital is more valuable than physical capital. You cannot put a price on human life. It is always more important than physical things. People's skills, knowledge, and experiences are more valuable than machines, production, computers, etc. It is seemingly impossible to really compare the two in my mind. Human capital will always win because you can't put a price on a human being's worth.
To organize each factor of production (land, labor and physical capital) human capital is required therefore human capital is more valuable than physical capital. Requirements of these two is also different. Physical capital requires many assets like building, machine, tools, etc. But human capital require skill, education, health and experience.
If there were no humans who wanted things there would be no point in having physical capital in the first place. Things can not feel, can not want, can not need, can not choose, can not reason. Things can not do anything, things are just things, tools, a means. Humans are more valuable. We are the end in and of itself.
Human capital is more important than physical because without it you would not have physical capital. Stone tools to computers, local farm implements to industrial commercial machinery, they all owe their existence to human capital. It is the knowledge, skill and creative brain of the human being that generates physical capital. So the short answer is Yes, human capital is more valuable than physical capital. Now if we are talking about investment in humans vs computers and the likely increase in robotic self learning and self awareness, well that is a whole different kettle of chicken.
There is no reason to believe that physical capital outweighs human capital whatsoever. In terms of "inalienable rights" evoked in the Declaration of Independence, the phrase used when referring to these rights were the right to "life, liberty, and the pursuit of happiness." While the pursuit of happiness could conceivably relate to physical pursuits, it is not nearly as vague as the right to life, which plainly states that no individual ought to be deprived of the right to life. As a result, physical capital could never outweigh human capital.
The capital it takes to train, educate, and wait for experience is more valuable than buying material resources. People can provide talent and services for a lifetime while most physical capital degrades or depreciates over time. You could take a bigger loss on someone quitting, becoming ill, death etc, verses losing material goods or wealth than can be a lot easier to replace if lost, broken or stolen, etc.
Yes, I agree that Human Capital can be fundamentally important in terms of skills, knowledge and experiences, however humanity as an economic factor of production is loosing its value, because we have to rely more and more on technology on achieve our ends and more on information that physical capital stores like the internet. Less and less economic production is being hand produced by hand in workshops and more and more production is being created by machines and technologies.
One could argue from here that humanity has embraced a different role in production through designing the technologies and machines that produce in our stead, but you must recognize the diminishing importance of humanity in that stage of production as well. Information is becoming increasing available to use on the internet, and programs which aid in design are being invented every single day. Humanity can deny the truth all it wants, but the reality is that the value and importance of human capital is falling.